Sheet-Like Element Such As A Net, Particularly For Geotechnical Applications

ABSTRACT

A sheet-like element, such as a net, particularly for geotechnical applications, comprising a sheet-like body formed by superimposing at least two sets of filaments in order to provide a lattice-like structure, the sheet-like body being provided by a first polymer, which defines the lattice-like structure, and a second polymer, which is coextruded together with the first polymer and affects at least regions of at least one face of the sheet-like body, the first polymer having physical and mechanical characteristics of compressive and tensile strength, while the second polymer has a high friction coefficient.

BACKGROUND OF THE INVENTION

As is known, sheet-like elements provided by means of a net having themost disparate shapes, obtained by extruding a plastic polymer, are usedin the geotechnical field.

The plastic polymer, generally constituted by polyethylene or propylene,is designed so as to have optimum compressive and tensile strength, soas to achieve the intended functionality and durability.

However, such solutions have a relatively high surface hardness, whichentails a limited possibility of grip of the net on the surface to whichit is applied.

Especially in cases in which the net is connected to a membrane of alandfill site or on the plastic wall for containing soil in general,waste sludge or sewage, the net would tend to slip, and it is thereforenecessary to use practical solutions which allow to stabilize the net inposition, creating a series of operations which are generally laboriousand expensive.

If the net is applied to a chemically compatible covering layer, such asfor example nonwoven fabric, or other nets having differentcharacteristics, it is necessary to increase the treatment temperatureso as to reach the surface melting point of the polymer that constitutesthe net, in some cases possibly degrading the inherent characteristicsof the product.

SUMMARY OF THE INVENTION

The aim of the invention is to eliminate the drawbacks cited above byproviding a sheet-like element, such as a net, particularly forgeotechnical applications, which can have optimum frictioncharacteristics which allow its easy application with the possibility tokeep the net in position without having to resort to additionalrefinements in application.

Within this aim, an object of the invention is to provide a sheet-likeelement which allows easier coupling of a layer, without damaging ordegrading the net proper.

Another object of the present invention is to provide a sheet-likeelement which, thanks to its particular constructive characteristics, iscapable of giving the greatest assurances of reliability and safety inuse.

Another object of the present invention is to provide a sheet-likeelement, such as a net, particularly for geotechnical applications,which can be obtained easily starting from commonly commerciallyavailable elements and materials and is also competitive from a merelyeconomical standpoint.

This aim and these and other objects, which will become better apparenthereinafter, are achieved by a sheet-like element, such as a net,particularly for geotechnical applications, according to the invention,comprising a sheet-like body formed by superimposing at least two setsof filaments in order to provide a lattice-like structure, characterizedin that said sheet-like body is provided by means of a first polymer,which defines said lattice-like structure, and a second polymer, whichis coextruded together with said first polymer and affects at leastregions of at least one face of said sheet-like body, said first polymerhaving physical and mechanical characteristics of compressive andtensile strength, said second polymer having a high frictioncoefficient.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention willbecome better apparent from the description of some preferred but notexclusive embodiments of a sheet-like element, such as a net,particularly for geotechnical applications illustrated by way ofnon-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic perspective view of the sheet-like body;

FIG. 2 is a schematic view of another embodiment of the sheet-likeelement;

FIG. 3 is a sectional view of the sheet-like body, with the secondpolymer on one face;

FIG. 4 is a sectional view of a sheet-like body with the second polymeron both faces;

FIG. 5 is a schematic perspective view of the application of an outerlayer to one face of the sheet-like body;

FIG. 6 is a sectional view of the application of an outer layer to oneface;

FIG. 7 is a perspective view of the application of an outer layer toboth faces of the sheet-like body;

FIG. 8 is a sectional view of the application of an outer covering layerto both faces.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures, the sheet-like element, such as a net,particularly for geotechnical applications, according to the invention,generally designated by the reference numeral 1, comprises a sheet-likebody 2, which is obtained by superimposing at least two sets offilaments which, by means of per se known techniques, are obtained byextrusion, so as to form a lattice-like structure.

In the exemplary embodiments shown, there are longitudinal filaments 2 aand transverse filaments 2 b, which intersect in order to form square ordiamond-shaped meshes, but of course the type of net may be any.

The sheet-like body 2 is obtained by means of a first polymer or basepolymer, constituted typically by polyethylene or polypropylene, whichhas the physical and mechanical characteristic of allowing excellentcompressive and tensile strength, thus transferring also to the netthese characteristics and achieving the required functional strength anddurability.

A particular characteristic consists in that the sheet-like body isobtained by coextruding a second polymer which provides regions 10, andwhich is chemically compatible with the first polymer, so as to obtain asingle mass without discontinuities.

The second polymer is again constituted by polyethylene orpolypropylene, which is filled with rubber-like materials, such as ethylvinyl acetate resins, so as to obtain a product which has a highfriction coefficient and further provides, on at least one face, theregions designated by the reference numeral 10 which have a reducedsurface hardness.

The first and second polymers cannot separate from each otheraccidentally or intentionally, since they have the same basic chemicalcomposition and, once extruded, form a single element, albeit withphysical characteristics of elasticity, hardness, color and the likewhich may be different.

The presence of the layer obtained by means of the second polymer allowsto have a net which can be applied easily in the different uses with theassurance that it remains in position, since the high frictioncoefficient prevents its movement.

Moreover, if the net is connected to an outer layer 20, it is possibleto use lower coupling temperatures, since the layer constituted by thesecond polymer has a lower melting point and accordingly it is possibleto apply the outer layer 20 at lower temperatures without damaging theinherent structure of the sheet-like body.

As clearly shown in the figures, it is possible to apply the outer layer20 to a single face or optionally to both faces, and in this case theregions made of the second polymer must be provided on both faces.

From what has been described above it is therefore evident that theinvention achieves the intended aim and objects, and in particular thefact is stressed that a sheet-like element, such as a net, is providedwhich allows to make all geotechnical applications particularlyadvantageous, thanks to the improved grip capacity of said net,improving the potential and characteristics of application of a productwhich has been known for some time.

Moreover, the possibility to allow easier coupling of the outer layerprovides the advantage of obtaining a product which does not damage theinherent structure of the net which is entrusted with mechanicalcompressive and tensile strength.

The invention thus conceived is susceptible of numerous modificationsand variations, all of which are within the scope of the appendedclaims.

All the details may further be replaced with other technicallyequivalent elements.

In practice, the materials used, as well as the contingent shapes anddimensions, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2006A000320 fromwhich this application claims priority are incorporated herein byreference.

1-11. (canceled)
 12. A sheet-like element, such as a net, particularlyfor geotechnical applications, comprising a sheet-like body formed bysuperimposing at least two sets of filaments in order to provide alattice-like structure, wherein said sheet-like body is provided bymeans of a first polymer, which defines said lattice-like structure, anda second polymer, which is coextruded together with said first polymerand affects at least regions of at least one face of said sheet-likebody, said first polymer having physical and mechanical characteristicsof compressive and tensile strength, said second polymer having a highfriction coefficient.
 13. The sheet-like element according to claim 12,wherein said first and second polymers are chemically compatible. 14.The sheet-like element according to claim 12, wherein said first andsecond polymers have the same basic composition.
 15. The sheet-likeelement according to claim 12, wherein said first and second polymersare polyethylene-based.
 16. The sheet-like element according to claim12, wherein said first and second polymers are polypropylene-based. 17.The sheet-like element according to claim 12, wherein said secondpolymer is filled with rubber-like materials.
 18. The sheet-like elementaccording to claim 12, wherein said second polymer is filled with ethylvinyl acetate resins.
 19. The sheet-like element according to claim 12,wherein said second polymer has a lower melting point than said firstpolymer.
 20. The sheet-like element according to claim 12, wherein saidsecond polymer affects at least regions (10) formed on both faces ofsaid sheet-like body.
 21. The sheet-like element according to claim 20,wherein said at least regions provided with said second polymer areadapted to act as an adhesive element for the connection of at least oneouter layer.
 22. The sheet-like element according to claim 12,comprising an outer layer which is applied to both parts of saidsheet-like body.